1. Field of the Invention
The present invention relates to a portable radiotelephone including a plurality of housings which are coupled so as to be overlapped each other.
2. Description of the Related Art
Conventionally, a folding type portable radiotelephone 2 shown in FIG. 7 is generally known as a folding type portable radiotelephone including two housings which can be folded. In the folding type portable radiotelephone 2, a display screen 12 such as LCD (Liquid Crystal Display) for displaying output information and a speaker 13 are provided on an inner face 10 of one housing 4, and a main operation section 17 and a microphone 15 are provided on an inner face 14 of another housing 6.
The main operation section 17 has a cursor key 18 for indicating upward, downward, right and left directions so that items displayed on the display screen 12 can be selected, and ten keys 20 for inputting numbers, characters, etc., and other keys for various functions.
However, the folding type portable radiotelephone 2 as shown in FIG. 7 has a problem that while the housing 4 and the housing 6 are folded, the display screen 12 cannot be seen unless the housings 4 and 6 are opened, and even though information is displayed on the display screen 12, the information cannot be browsed in a folded state.
In order to solve such a problem that it is troublesome and annoying to open the housings 4 and 6, there have been proposed some mobile phone sets in which the display screen 12 is directed outward even in the folded state or in a state corresponding to the folded state. Examples of the mobile phone sets of this type are the overlapping type mobile phone sets disclosed in JP-A-H11-215218, JP-A-2002-141984 and JP-A-2002-135380.
These overlapping type mobile phone sets are so designed that the display screen provided on one of the housings is directed inward in a state where two housings to be coupled are opened, which is substantially same manner as the folding type portable radiotelephone 2 as shown in FIG. 7. However, different from the above described folding type portable radiotelephone 2, the overlapping type mobile phone sets are so designed that one of the housings can be folded and overlapped on another housing by twisting it by 180 degree at a coupling section between the two housings. Therefore, the display screen can be directed outward, even in a state where the two housings are overlapped.
Disclosed in JP-A-H07-288860 is another type of the conventional overlapping type portable radiotelephone. This overlapping type portable radiotelephone is so designed that one housing having the display screen and another housing having the operation section are coupled in an overlapped state which the display screen and the operation section are directed in the same direction, through a shaft which is provided in a direction of passing through these two housings.
This overlapping type portable radiotelephone can be opened, by rotating one housing with respect to another housing around the shaft by such an action as spreading a fan, and also, the two housings can be kept overlapped each other with the display screen directed outward.
Since the two housings can be kept in the overlapped state with the display screen directed outward in these overlapping type mobile phone sets, the information on the display screen can be browsed while the two housings are kept in the overlapped state. However, in the case of starting a call, the two housings must be opened as well as the conventional folding type portable radiotelephone 2.
On the other hand, with the overlapping type portable radiotelephone disclosed in JP-A-2000-196720, it is possible to browse the information on the display screen while two housings are in the overlapped state, and it is also possible to start a call while the two housings are in the overlapped state.
However, according to the related arts disclosed in the above JP-A-H11-215218, JP-A-2002-141984, JP-A-2002-135380 and JP-A-H07-288860, when a user receives an incoming call, he must open the two housings to start the telephone conversation.
Therefore, it takes labor to start the conversation. Besides, in the case where the user lately becomes aware of the incoming call, he will be unable to put the portable radiotelephone into a state available for conversation before a person on the other end of the phone disconnects the call. This will make the person on the other end disagreeable, and convenience of the portable radiotelephone cannot be fully achieved.
On the other hand, according to the related art disclosed in the above JP-A-2000-196720, the folding type portable radiotelephone can be brought into a state available for conversation at once, because the conversation can be had even in the closed state. However, there is a problem that because a length of the downsized portable radiotelephone is too short in the closed state, when the speaker comes near the user's ear, the microphone does not close to the user's mouth, which will make the user uneasy.